class Solution {
    int dx[4] = {0, 0, -1, 1};
    int dy[4] = {1, -1, 0, 0};
    int m,n;
    int prev;
public:
    vector<vector<int>> floodFill(vector<vector<int>>& image, int sr, int sc, int color) {
        if(image[sr][sc]==color)return image;

        m=image.size(),n=image[0].size();
        prev=image[sr][sc];
        dfs(image,sr,sc,color);
        return image;
    }
    void dfs(vector<vector<int>>& image, int i, int j, int color)
    {
        image[i][j]=color;
        for(int k=0;k<4;k++)
        {
            int x = i + dx[k], y = j + dy[k];
            if(x >= 0 && x < m && y >= 0 && y < n 
            && image[x][y] == prev)
            {
                dfs(image,x,y,color);
            }
        }
    }
};
